Exosomal miR-205-5p contributes to the immune liver injury induced by trichloroethylene: Pivotal role of RORα mediating M1 Kupffer cell polarization

Trichloroethylene (TCE) is a common environmental contaminant that can induce occupational dermatitis medicamentosa-like TCE (ODMLT), where the liver damage is the most common complication. The study aims to uncover the underlying mechanism of TCE-sensitization-induced liver damage by targeting specific exosomal microRNAs (miRNAs). Among the enriched serum exosomal miRNAs of ODMLT patients, miR-205-5p had a significant correlation coefficient with the liver function damage indicators. Moreover, retinoic acid receptor-related orphan receptor alpha (ROR alpha) was identified as a direct target of miR-205-5p via specific binding. Further experiments showed that kupffer cells (KCs) underwent M1 phenotypic and functional changes in liver injury induced by TCE which were alleviated by reducing the expression of miR-205-5p. However, this alleviation was reversed by the ROR alpha antagonist SR1001. In vitro experiments showed that miR-205-5p promoted M1 polarization of macrophages and enhanced the secretion of inflammatory factors by regulating ROR alpha. An increase in ROR alpha reversed the polarization direction of M1-type macrophages and reduced the secretion of proinflammatory factors. In addition, pretreatment of mice with SR1078, a specific ROR alpha agonist, effectively blocked M1 polarization of KCs and reduced the severity of TCE-induced liver injury. Our study uncovers that miR-205-5p regulates KC M1 polarization by targeting ROR alpha in immune liver injury induced by TCE sensitization, providing new insight into the molecular mechanisms and new therapeutic targets for ODMLT.